1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // UNSUPPORTED: libcpp-has-no-threads 11 12 // FLAKY_TEST 13 14 // <mutex> 15 16 // template <class Mutex> class lock_guard; 17 18 // explicit lock_guard(mutex_type& m); 19 20 // template<class _Mutex> lock_guard(lock_guard<_Mutex>) 21 // -> lock_guard<_Mutex>; // C++17 22 23 #include <mutex> 24 #include <thread> 25 #include <cstdlib> 26 #include <cassert> 27 28 #include "test_macros.h" 29 30 std::mutex m; 31 32 typedef std::chrono::system_clock Clock; 33 typedef Clock::time_point time_point; 34 typedef Clock::duration duration; 35 typedef std::chrono::milliseconds ms; 36 typedef std::chrono::nanoseconds ns; 37 f()38void f() 39 { 40 time_point t0 = Clock::now(); 41 time_point t1; 42 { 43 std::lock_guard<std::mutex> lg(m); 44 t1 = Clock::now(); 45 } 46 ns d = t1 - t0 - ms(250); 47 assert(d < ms(200)); // within 200ms 48 } 49 main()50int main() 51 { 52 m.lock(); 53 std::thread t(f); 54 std::this_thread::sleep_for(ms(250)); 55 m.unlock(); 56 t.join(); 57 58 #ifdef __cpp_deduction_guides 59 std::lock_guard lg(m); 60 static_assert((std::is_same<decltype(lg), std::lock_guard<decltype(m)>>::value), "" ); 61 #endif 62 } 63